
#ifndef __base_template_util_h__
#define __base_template_util_h__

#pragma once

namespace base
{

	// template definitions from tr1

	template<class T, T v>
	struct integral_constant
	{
		static const T value = v;
		typedef T value_type;
		typedef integral_constant<T, v> type;
	};

	template<class T, T v> const T integral_constant<T, v>::value;

	typedef integral_constant<bool, true> true_type;
	typedef integral_constant<bool, false> false_type;

	template<class T> struct is_pointer : false_type {};
	template<class T> struct is_pointer<T*> : true_type {};

	template <class T, class U> struct is_same : public false_type {};
	template <class T> struct is_same<T,T> : true_type {};

	template<class> struct is_array : public false_type {};
	template<class T, size_t n> struct is_array<T[n]> : public true_type {};
	template<class T> struct is_array<T[]> : public true_type {};

	template<class T> struct is_non_const_reference : false_type {};
	template<class T> struct is_non_const_reference<T&> : true_type {};
	template<class T> struct is_non_const_reference<const T&> : false_type {};

	template<class T> struct is_void : false_type {};
	template<> struct is_void<void> : true_type {};

	namespace internal
	{

		// Types YesType and NoType are guaranteed such that sizeof(YesType) <
		// sizeof(NoType).
		typedef char YesType;

		struct NoType
		{
			YesType dummy[2];
		};

		// This class is an implementation detail for is_convertible, and you
		// don't need to know how it works to use is_convertible. For those
		// who care: we declare two different functions, one whose argument is
		// of type To and one with a variadic argument list. We give them
		// return types of different size, so we can use sizeof to trick the
		// compiler into telling us which function it would have chosen if we
		// had called it with an argument of type From.  See Alexandrescu's
		// _Modern C++ Design_ for more details on this sort of trick.

		struct ConvertHelper
		{
			template <typename To>
			static YesType Test(To);

			template <typename To>
			static NoType Test(...);

			template <typename From>
			static From Create();
		};

		// Used to determine if a type is a struct/union/class. Inspired by Boost's
		// is_class type_trait implementation.
		struct IsClassHelper
		{
			template <typename C>
			static YesType Test(void(C::*)(void));

			template <typename C>
			static NoType Test(...);
		};

	} //namespace internal

	// Inherits from true_type if From is convertible to To, false_type otherwise.
	//
	// Note that if the type is convertible, this will be a true_type REGARDLESS
	// of whether or not the conversion would emit a warning.
	template<typename From, typename To>
	struct is_convertible
		: integral_constant<bool,
		sizeof(internal::ConvertHelper::Test<To>(
		internal::ConvertHelper::Create<From>())) ==
		sizeof(internal::YesType)> {};

	template<typename T>
	struct is_class
		: integral_constant<bool,
		sizeof(internal::IsClassHelper::Test<T>(0)) ==
		sizeof(internal::YesType)> {};

} //namespace base

#endif //__base_template_util_h__